Charging base



FIG. 1 is a top plan view of the charging base showing my new design;

FIG. 2 is a left side view thereof;

FIG. 3 is a front view thereof;

FIG. 4 is a rear view thereof;

FIG. 5 is a right rear perspective view thereof;

FIG. 6 is a front perspective view thereof;

FIG. 7 is a top perspective view thereof; and,

FIG. 8 is a left rear perspective view thereof.

The ornamental design for a charging base, as shown and described.